


It Takes Teamwork to Tame A Beast

by brooklynapple



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: F/F, Monsterfucking, Multi, Polyamory, constance's dark magic demon strap, everyone takes such good care of mari, feral marianne
Language: English
Status: Completed
Published: 2020-11-01
Updated: 2020-11-01
Packaged: 2021-03-09 03:47:39
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,754
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27317992
Author URL: https://archiveofourown.org/users/brooklynapple/pseuds/brooklynapple
Summary: Hilda and her wife Marianne visit Hapi and Constance at House Nuvelle shortly before the full moon. The three of them team up to give Marianne exactly what she craves during her monthly transformation.
Relationships: Hapi/Constance von Nuvelle, Marianne von Edmund/Hilda Valentine Goneril, Marianne von Edmund/Hilda Valentine Goneril/Hapi/Constance von Nuvelle
Comments: 2
Kudos: 25
Collections: FE3H Monsterfucking Weekend 2020, FE3H Polyship Week





	It Takes Teamwork to Tame A Beast

**Author's Note:**

> Written for the glorious confluence of #FE3HMonsterfuckingWeekend and #FE3HPolyship week. I adore both Marihilda and Hapistance and think that the four of them would get along swimmingly!

“Hilda! We are so very delighted that you decided to join us this time!” Constance’s curtsy had the exact proper amount of depth and flourish for a greeting from a noble of her station to a noble of Hilda’s. 

“Constance, Hapi, so good to see you both!” Hilda grinned as she entered the lavishly-appointed bedroom in Nuvelle Manor, leading Marianne with her by the hand. “Mari’s been raving so much about what a fantastic time she has when she visits you here at House Nuvelle that I thought I’d come along and see what the fuss was all about.”

“Heya scary Mari,” Hapi drawled. “You got here just in time. Moon time is in what, just a few hours?”

“Yes, and I have to admit it’s been a very trying day of travel this close to my transformation.” Marianne immediately made her way to the large bed that dominated the room, set against a wall to which metal rings and chains had been fastened. “I’m very glad to see you both. Normally I would love to relax for a bit and catch up over some tea, but given how close we are to moonrise I hope you’ll forgive me if I jump right into our normal preparations and precautions.”

“A very sensible and commendable thing to do in these circumstances,” Constance replied with a nod. “Of course we understand. While you’re getting settled in your customary place, Hapi and I can bring your lady wife up to speed on our plan for the evening.”

“Yes, we didn’t mean to cut it so close,” Hilda said. “We ran into a storm off the coast of Derdriu and had to wait it out. Next time we’ll leave a day earlier just in case. I felt so bad seeing my poor Mari so agitated while traveling!” She turned her attention to Constance. “So what’s all this about a plan? I know all about taking care of Marianne during her moon time, of course, so I doubt there’s much you’ll need to fill me in on.”

“No doubt you are quite experienced,” Constance replied, “but Hapi and I have special...skills and techniques that we think you might be interested in hearing about.”

Hilda smiled wickedly. “That’s exactly what I came here to see. Do go on!”

While Constance and Hilda continued chatting in increasingly conspiratorial tones, Hapi helped Marianne undress and get settled against the bed’s sturdy, metal-reinforced headboard. “Every time we do this I remember all over again how pretty you are, Mari.” She smiled and gave Marianne a kiss on her bare shoulder.

Marianne blushed and giggled. “Thank you Hapi, that’s so sweet. Especially since you mostly see me during the full moon when I’m at my least pretty.”

“Uh uh, no more talk like that, silly. This is me, Hapi, remember? I think you’re absolutely gorgeous when you’re covered in those shimmery scales and have that long, graceful tail and those fascinating golden eyes. I just want demonic Mari to eat me right up.”

Marianne leaned over to give Hapi a kiss. “I feel so lucky having all of you here to appreciate this side of me. Truly.” She held both hands out to Hapi, palms up. “But demonic Mari really will eat you up if we don’t get me properly secured before the moon rises. Can you give me a hand?”

Hapi smiled and reached for one of the chains fastened to the wall behind the bed. At its end was a thick metal cuff lined in soft fur. She fastened it securely around Marianne’s wrist, and bound her other wrist in the same fashion. She tugged on them to make sure they were secure, and gave Marianne a thumbs up.

“These are all set. Do you want me to do your legs too?”

Marianne smiled at her. “I don’t think that will be necessary with you and Hilda here to keep me calm. I mostly want my arms bound just to make sure I don’t scratch any of you too badly.”

Hapi grinned. “Admit it, it’s also pretty nice to be all tied up and helpless like that, right? I know it really gets me going when Constance does it to me.”

Marianne’s blush deepened as she laughed. “I suppose there’s no point in trying to hide that from my monster-whisperer.”

Hapi glanced over at Constance and Hilda, who were still talking animatedly. She rolled her eyes. “Speaking of monster management, let me go herd those two over here before they miss the whole show. If my lady will excuse me.”

She gave Marianne a comically exaggerated bow, and beamed with delight at the sound of Marianne’s laughter.

“Are you two just about ready? It’s time to get this show on the road.”

“Already?” Hilda asked. “But moonrise isn’t for another hour at least! I thought you two were just getting in some last-minute kinky action over there before Mari’s transformation started.” 

“Oho, but this is where Hapi’s special talents shine!” Constance exclaimed. “Tell her, Hapi!”

“We discovered that I can use my sighs to start her transformation early, if we want.” Hapi explained. “It still has to be close to the full moon for it to work, but we can make it a bit more predictable this way. And once she transforms, I can use my monster taming abilities to calm her so that nothing gets out of control.”

Hilda looked impressed. She turned to Marianne. “And I assume this is all okay with you, Mari? I know you’ve only had good things to say about your visits with Hapi and Constance.”

Marianne smiled and nodded. “Definitely. The way that Hapi calms me feels different than the way I feel calm and safe with you, Hilda, but it still makes the process much easier. And the, um, other things they do while I’m transformed are also quite nice.”

“Hmm, yeah, Constance has been telling me about some of those ‘other things’,” Hilda said with a grin. “I can’t wait to see them in action.”

“In that case, let us begin!” Constance exclaimed with a flourish. She untied the simple yet elegant robe she was wearing to reveal intricate purple and gold lingerie underneath. Hilda whistled in appreciation.

“Absolutely gorgeous craftsmanship,” she said. “You’ll have to tell me who does your tailoring.” She slipped off her own robe to show off her equally intricate and predictably pink lingerie ensemble.

Hapi, meanwhile, had stripped completely naked, tossing her loose tunic and pants to one side and standing next to Marianne wearing nothing but a soft leather choker that covered most of her neck. She gave Hilda and Constance a quick glance and then turned her full attention to Marianne, cupping Marianne’s cheek in her hand. “You ready for this?”

Marianne was writhing restlessly in her chains and had broken out into a light sweat. She calmed a bit at Hapi’s touch and turned her head to kiss her palm. “Yes, please. Let’s get started. I can feel the transformation coming on already.”

Hilda and Constance gathered around the bed. Hilda gave Marianne a gentle, reassuring kiss, and then nodded at Hapi. Hapi took a deep breath and gave a careful, controlled sigh while staring steadily at Marianne. 

Marianne cried out and went rigid in her bonds. Her eyes glowed a deep red, and her body contorted. Magic swirled around her. Her skin began to harden and crack as scales emerged, and her hands extended into long talons with razor-sharp claws. Her eyes stretched into a slitted, reptilian shape, and her jaw elongated and sprouted long, pointed teeth. A sinuous, forked tongue flickered out to taste the air around her.

She let out a low growl and began to thrash and pull against the chains binding her to the wall. 

“Shhh,” Hapi said, and began to murmur at her in a firm, quiet voice. 

At the same time, Hilda put her hands on Marianne’s shoulders and leaned over to nuzzle against her. “It’s okay, sweetie, I’m right here. Hapi and Constance are here too. We’re gonna take good care of you and give you just what you need.”

Marianne calmed instantly, and her growls turned to whines and whimpers as she looked in turn at the three women around her. Her voice, when she was finally able to use it, was a strange, guttural mixture of human and beast. “Hilda...Hapi...please...I need...I need you to...” She writhed on the bed and thrust her hips upward.

“Much better,” Constance declared. “Now then, Hapi, show me what she’s thinking,” 

Hilda snorted out a laugh. “Trust me, you don’t need any special magic to know what Mari’s thinking when she’s like this. The only thing on her mind is ‘want to scratch and bite and fuck.’”

Constance rolled her eyes indignantly. “Obviously, but such observations are too general for my purposes. I need specificity. You will see exactly why in one moment. Hapi?”

Hapi took Constance’s outstretched hand, then put her other hand on Marianne’s heaving chest. Her eyes glowed a brilliant white. 

Constance closed her eyes in concentration. “Aha, yes, I see...oho, you want it like  _ that _ do you? Very well! A moment more, Hapi!” She raised her free hand and dark magic began to gather around her. It coalesced in a swirling mass at the level of her groin, where it began to form a distinctly phallic-looking shape.

Hilda cackled in delight. “Ooh yes, this is the part I was waiting for!”

“Shh!” Constance hissed. “I’m  _ concentrating. _ ”

The magic phallus continued to lengthen and thicken until it had far surpassed any realistic human proportion. A scaly texture began to form on its surface, and spikes and ridges extruded at regular intervals along its length. Hilda stopped laughing and stared at it with wide eyes, a mixture of shock and admiration on her face.

With a final, sparkly flourish, Constance dropped Hapi’s hand and opened her eyes. “There!” she announced proudly, turning to Hilda. “When our dear Marianne enters this state and says she ‘wants to fuck’, as you so crudely put it,  _ this _ is what she has in mind. And thanks to my magic genius and Hapi’s special talent, we are only too happy to give our darling monster girl what she needs.”

For the first time all evening, and possibly all week, Hilda was at a loss for words.

Marianne’s eyes widened at the sight of Constance’s demonic magic cock, and she whined and strained against her bonds. “Yes...please...give it to me. Want it so bad…” She spread her legs wide, giving them all a view of the juices running freely down her thighs.

“Of course, my dear,” Constance said matter-of-factly as she climbed on the bed. “House Nuvelle is at your service.”

“I see you’ve learned that foreplay is pretty much useless when she’s like this,” Hilda observed. “Once she transforms, she just wants to fuck over and over. It’s pretty hot.” She grinned. “I’ve given her my strap a bunch of times during the full moon, but never anything like  _ that. _ I can’t wait to see what happens.”

Constance settled herself between Marianne’s scaly, outspread legs and looked smugly over at Hilda. “Luckily for you, your wait is over. And so is Marianne’s.” 

Grasping Marianne’s hips with both hands, she angled the toy and pressed the ridged, flared head just inside Marianne’s entrance.

Marianne’s reaction was immediate as the magic demonic cock stretched her open. She let out a yowling, snarling growl and clawed at the air. Hapi whispered reassuringly to her as Constance eased the entire cock inside her bit by bit. Hilda watched in fascination, noting that the spines flattened and retracted as they slid inside her writhing, whining lover.

Constance shuddered in pleasure as she pressed the thick cock fully inside Marianne. She began making small motions with her hips, moving in and out just a bit so that Marianne could get used to the sensation. Marianne whimpered and thrust her hips upwards, seeking more.

“I lack the proper words to describe this sensation,” Constance panted, “but allow me to share that being inside a demonic beast feels very different than being inside a human woman. There is something much more raw, and primal, and...spiky.”

“Wow,” Hilda said, watching with rapt attention. “I definitely need to try that out myself sometime.”

Marianne growled again and fixed her reptilian eyes on Constance. “Please, more. It feels so good, but I need it harder. And bigger, if you can.”

“Absolutely, we were just getting warmed up.” Constance made a quick gesture, and her eyes glowed with dark magic. Marianne cried out in pleasure and Constance began fucking her with a hard, steady pace, drawing the cock almost all the way out before slamming it back into Marianne with a precise snap of her hips. Hilda noted with appreciation that it was longer and thicker than it had been moments before, with even more ridges and spines.

“I see that I’m going to have to make some adjustments to my straps when we get home, hmm Mari?”

Marianne was too far gone to reply, snarling and whimpering in pleasure each time Constance thrust roughly into her.

Hapi, meanwhile, stretched out alongside Marianne on the bed and slid a hand down her stomach. “That’s a good Mari-beast. Your scales feel so nice and tickly. Let me help Coco make you feel good.” She moved her hand down between Marianne’s legs and found her clit, which had grown larger with her transformation and unsheathed itself from its scaly hood. She used two fingers to rub and stroke it in time with Constance’s thrusts, and Marianne let out a whimpering snarl and bucked her hips in response. 

Hilda crawled up the bed on the other side of Marianne and murmured into her ear, too softly for Hapi or Constance to hear. Then she said a bit louder “Do you think you can do that for me, Mari, while Hapi and Constance take good care of you?” Marianne turned to look at her, panting and covered in sweat, and growled her assent. 

Hilda beamed. “That’s my amazing girl. Pay attention, you two. I have a trick or two of my own I can show you!” She shimmied out of her panties and straddled Marianne’s head, looking into her yellow, reptilian eyes. 

“Now remember the rules, Mari. You can bite my thighs, but no biting the more sensitive bits.” In response, Marianne extended her long, forked tongue and flicked it between Hilda’s legs. Hilda sighed in pleasure. “The things she can do with this tongue will make your eyes roll back in your head.”

Hilda grabbed onto the headboard and began to moan softly as Marianne put her tongue to work. At the other end of the bed, Hapi and Constance redoubled their efforts, stroking and fucking Marianne relentlessly until her thighs began to shake. 

She threw back her head and let out a loud, whining growl, then sunk her teeth into Hilda’s thigh hard enough to draw blood. Hilda cried out in surprise, then let out a gasping laugh.

“Good girl, remembering the rules even when you must be so distracted by how well Constance and Hapi are fucking you. Do you think you can keep going with your tongue? I’ll bet you can make me come at the same time that they make you come.”

Marianne writhed and whimpered underneath her, but managed to nod her head. She passed her tongue over Hilda’s thigh to lick away the blood, and then plunged it into her core again. Hilda moaned happily and closed her eyes.

Marianne’s hips jerked suddenly, and Constance exclaimed in shock. “Oh! Oh my!” She was buried inside Marianne to the hilt but had completely stopped thrusting.

“Coco, is everything okay?”

“Yes, I...it seems my magic, ah, instrument is reacting as Marianne gets close to finishing. The um, the spines have extended inside her and locked themselves in place, and her body is doing some very, ah, interesting things to it.” She let out a low moan. “It feels strange, but... _ oh goddess _ ...not unpleasant.”

“Ooh, nice.” Hapi grinned. “I’ve always wondered how these sort of things worked with demonic beasts.”

“You-you have?” Constance asked breathlessly, grinding herself into Marianne.

“Yep. And now you and Marianne can tell me all about it! It looks pretty hot.” Hapi glanced over at Hilda, moving her hips rhythmically against Marianne’s face while riding her long, sinuous tongue. “Am I the only one not getting off here? Gotta fix that.”

She let out a tiny, barely audible sigh, and a small tentacle appeared. “Hey little guy. Mind giving me a hand while I help finish off our beast girl here?” She slipped the tentacle inside herself with a happy moan, and bent down to suck and lick at Marianne’s engorged clit.

Marianne let out a low, muffled growl and her hips spasmed again. Her whole body contorted, and Constance cried out on top of her. 

“Goddess, it’s...it’s as though she’s pulling the magic essence out of my conjuration while it’s inside her.” She moaned. “Truly fascinating, and-  _ ahhh- _ very stimulating.”

Hapi raised her head from Marianne’s clit and grinned, lips glistening. “So you’re coming inside her with your huge magic demon cock? That sounds amazing.”

Whatever response Constance tried to give was swallowed by a loud moan as her hips bucked uncontrollably on top of Marianne. 

At the head of the bed, Hilda moaned loudly. “Yes, please, just like that. Ohhhh goddess your tongue feels so amazing inside me. Fuck...Marianne…” She came with a sharp cry, smearing wetness across Marianne’s face.

Marianne moved her hips faster and faster, pulling against the chains that held her and letting out a muffled yowl as Hilda rode out her pleasure on top of her. As Hilda finished and slumped next to her, she let out a sound that was half-howl, half-moan and her eyes glowed red again. “So close...give me all of it inside...need more…”

Constance cried out and her eyes lit up with dark magic energy. She braced herself with both hands on Marianne’s body as she felt Marianne draw even more essence from her twitching, spasming magic cock. 

Hapi and Hilda stared in awe as Constance and Marianne writhed together on the bed, in thrall to the forces and urges coursing through them. Moments passed. 

At last, Marianne let out a guttural, unearthly scream, and her body went rigid. Constance cried out and collapsed on top of Marianne. The glow dimmed from both of their eyes, and Marianne shuddered and went limp. 

As she lay on the bed panting with closed eyes, her demonic transformation began to fade. Scales softened back into human skin, her teeth and claws retracted to their normal lengths, and her face once again resembled the delicate, human Marianne that they all knew so well.

Hapi pulled Constance off of Marianne and into her lap, where she wiped her sweaty brow and cooed softly at her. Hilda unshackled Marianne and began rubbing her arms and wrists, looking down at her with an expression that was both tender and curious.

“That’s right my Marianne, you were such a good girl today. I’m so proud of you. But here you are back to normal already, and the moon is still high in the sky. Any idea what happened?”

Marianne blinked and looked up at Hilda with a sleepy smile. “I-I think Constance’s magic somehow sated the beast inside me. I still feel the pull of the moon, but it’s much fainter now, and I don’t think the beast is going to come back.”

Hilda looked over at Hapi and Constance, snuggled together on their side of the bed. “You’ve done this with her before, right? Does this always happen?”

Constance smiled weakly, a hint of triumph evident in her eyes. “I must admit, while it is true we have done this before, we have never before achieved this result. We also have not been nearly as, um, vigorous when we’ve entertained our dear Marianne in the past. Nor has she ever asked in her beast form for an implement that was quite so…large and imposing. Perhaps she felt more comfortable expressing her full desires because you were present.”

“Is that right, Mari?” Hilda gazed adoringly at Marianne and gave her a kiss on her nose. “Did you feel safe letting out your full horny sex beast side because I was here? That’s so cute!”

Marianne giggled, and Hilda leaned down to give her a deep, lingering kiss.

Hapi watched them fondly as she absently stroked Constance’s curls. “You did a great job tonight too, Coco. You fucked the beast right out of her. I didn’t even know that was possible.”

Constance tried to look smug, but the blush on her cheeks gave her away. “It took our combined genius to make it happen, of course. I couldn’t have done it without you.” She kissed Hapi’s cheek. “Though this does suggest some fascinating hypotheses about the role of dark magic in demonic beast mating behavior and reproduction. I shall have to conduct further research when the hour is not quite so late!”

Hapi grinned. “I’m sure Marianne would be happy to answer any questions you might have. Isn’t that right, scary Mari?”

Marianne yawned and smiled at them from where she rested comfortably in Hilda’s arms. “Of course, though I should warn you that my memory is always a bit hazy when it comes to my transformations. If you really want to research further, you should come visit Edmund Manor sometime. Our family’s library has an extensive collection of demonic beast lore because of the unique nature of our crest.”

“Ooh yes, we would love to have you come visit us!” Hilda exclaimed. “Perhaps we could make this a regular thing. I’d love to see what else Constance can do with her dark sex magic. And those tentacles that Hapi calls up are just too cute.” 

“It would of course be our great honor to visit you both at Edmund Manor,” Constance replied, her attempt at a proper response somewhat undermined by an enormous yawn. “But for now, you are both still our guests. Let us all get some rest, and in the morning you shall experience even more of the legendary hospitality of House Nuvelle. Isn’t that right, Hapi?”

Hapi’s only response was a loud snore, as she had already fallen fast asleep.

**Author's Note:**

> For more horny and wholesome monsterfucking action (and more!) you can follow me on [Twitter](https://twitter.com/quorniya).


End file.
